Interactive cosmos tools
Free, interactive calculators that make the cosmos tangible — from your weight on Mars to the size of a black hole. No sign-up, works on every device.
Your weight on other planets
How much would you weigh on Mars, the Moon or Jupiter?
Open tool →Your age on other planets
How old would you be if you were born on Mars?
Open tool →Black hole calculator
How big would a black hole of any mass be?
Open tool →Redshift calculator
From redshift to recession speed and distance.
Open tool →Telescope calculator
Magnification, exit pupil & resolution of your telescope.
Open tool →Cosmic calendar
13.8 billion years shrunk into a single year.
Open tool →Light travel time calculator
How old is the light you see in the sky?
Open tool →Cosmic size comparison
From Earth to giant stars: sizes that break the mind.
Open tool → Newsletter · free
The cosmos in your inbox
Once a week: the best of the universe, made simple.
Welcome gift: a cheat sheet of 50 cosmic facts. Preview the 50 facts →
- Every week
- Always free
- No spam